1. Field of the Invention
The present invention relates to a method for manufacturing a disk drive device and a disk drive device manufactured by same, and in particular, a method for manufacturing a disk drive device which reduces the amount of adhering particles and a disk drive device manufactured by same.
2. Description of the Related Art
Recently, disk drive devices like an HDD (Hard Disk Drive) need to meet requirements, such as downsizing and increasing of the capacity. For example, a disk drive device that records magnetic data rotates a recording disk having recording tracks at a high speed, and reads/writes data while causing a magnetic head to float over the recording tracks while maintaining a tiny clearance. In order to downsize such a disk drive device and increase the capacity thereof, it is necessary to make the pitch of the recording tracks narrower. Moreover, together with the narrowing down the pitch of the recording tracks, it is also examined to further narrow down the clearance between the magnetic head and the recording disk. For example, it is necessary that the clearance between the magnetic head and the recording disk is designed as an extremely tiny clearance like equal to or less than 10 nm.
Moreover, in order to downsize the disk drive device, a magneto-resistance effect element (hereinafter, referred to as an MR element) is used for the magnetic head. On the other hand, when the MR element is used in a tiny space, the magnetic head may cause a thermal asperity failure (hereinafter, referred to as a TA failure) and a head-crush failure. More specifically, a TA failure is a phenomenon in which tiny foreign materials on the surface of the recording disk contact the MR element while the magnetic head is in a floating tracing operation, and the kinetic energy of such foreign materials produces heat to the MR element momentarily, the MR element is heated or cooled instantaneously, the resistance of the MR element instantaneously changes, and the changed resistance is superimposed on a playback signal as noises, thereby disturbing an accurate reading of the playback signal.
Through the examination by the inventors of the present invention, the inventors of the present invention found that the TA failure is caused when foreign materials (hereinafter, referred to as “particles”) of 0.1 μm to several μm or so adhering to the disk drive device adhere to the surface of the recording disk due to vibration, and airflow, etc. JP 2010-244627 A discloses a cleaning device that cleans various components like a base.
Even if the base, etc., is cleaned, particles may adhere to the base when components like a bearing unit and a hub are assembled. For example, the following first case can be expected in which particles adhering an assembling facility, a tool, or a hand of a worker are transferred to the disk drive device.
Moreover, the following second case can be also expected in which when a bond is used to assemble the bearing unit and the hub, etc., to the base, components contained in such a bond fly apart from the bond and adhere to the surfaces of the base, the bearing unit, and the hub as particles.
Furthermore, the following third case can be expected in which when soldering or welding, etc., is performed in order to connect electrical wirings of a drive unit, etc., particles flay apart at the time of soldering or welding, and adhere to the surfaces of the base, the drive unit and the hub as particles.
The particles adhered at the time of assembling as explained above cannot be eliminated by the conventional methods for manufacturing a disk drive device, and the level of the cleanness in the general disk drive devices is low. When the large amount of the particles remains in the interior of the disk drive device, if the clearance for floating the magnetic head is reduced, the occurrence rate of the TA failure increases, disturbing the accomplishment of the downsizing of the disk drive device and the increase of the capacity thereof.
The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a technology which increases the cleanness level in a disk drive device, and which can maintain a low occurrence rate of a TA failure when a clearance between a magnetic head and a recording disk at the time of the tracing operation of the magnetic head is reduced.